Process for producing microparticles laden with a volatile organic active

Abstract

The present invention relates to a process for producing microparticles laden with at least one active, wherein the microparticles are formed from a thermoplastic organic, polymeric material and in the unladen state, in their interior, have at least one cavity connected via pores to the surface of the microparticles, wherein (a) a composition of unladen microparticles are impregnated with a liquid comprising the active, whereby laden microparticles are obtained, which contain in the interior cavity the liquid, and (b) subjecting the laden microparticles to thermal treatment by passing a stream of free flowing laden microparticles in a carrier gas through a heated zone at a temperature of at least 20 K, in particular at least 40 K, e.g. 20 to 250 K especially 40 to 200 K above the softening temperature of the thermoplastic organic polymeric material, where the average residence time of the laden microparticles in the heated zone is not more than 60 s, in particular not more than 30 s, especially not more than 20 s or not more than 10 s, e.g. in the range of 0.1 to 60 s, in particular in the range of 0.1 to 30 s, more particularly in the range of 0.5 to 20 s and especially in the range of 1 to 10 s. The present invention further relates to compositions of microparticles filled with at least one active, in particular with at least volatile organic active, which is obtainable by a process of the invention, and to the use thereof, especially in a product selected from perfumes, washing and cleaning compositions, cosmetic compositions, personal care compositions, hygiene articles, foods, food supplements, fragrance dispensers and fragrances. The present invention further relates to products comprising an inventive composition of microparticles filled with at least one active, in particular with at least one volatile organic active, and to the use thereof, especially for controlled release of actives of low molecular weight and specifically for controlled release of aroma chemicals.

1 .- 16 . (canceled) 
     
     
         17 . A process for producing microparticles laden with at least one active, wherein the microparticles are formed from a thermoplastic organic, polymeric material and in the unladen state, in their interior, have at least one cavity connected via pores to the surface of the microparticles, wherein
 (a) a composition of unladen microparticles are impregnated with a liquid comprising the active, whereby laden microparticles are obtained, which contain in the interior cavity the liquid, and   (b) subjecting the laden microparticles to thermal treatment by passing a stream of free flowing laden microparticles in a carrier gas through a heated zone at a temperature of at least 20 K above the softening temperature of the thermoplastic organic polymeric material, where the average residence time of the laden microparticles in the heated zone is not more than 60 s.   
     
     
         18 . The process according to  claim 17 , where the temperature in the heated zone is in the range from 130 to 350° C. 
     
     
         19 . The process according to  claim 17 , where the softening temperature of the thermoplastic organic polymeric material is in the range from 50 to 160° C. 
     
     
         20 . The process according to  claim 17 , where the heating zone has a straight tubular geometry. 
     
     
         21 . The process according to  claim 17 , where the mass density of the stream of free flowing laden microparticles passed through the heated zone is in the range from 5 to 500 g/m 3 . 
     
     
         22 . The process according to  claim 17 , where the stream of free flowing laden microparticles is quenched immediately after leaving the heated zone. 
     
     
         23 . The process according to  claim 17 , wherein the thermoplastic organic, polymeric material comprises at least one polymer having a glass transition temperature or melting point in the range from 45 to 140° C. 
     
     
         24 . The process according to  claim 17 , wherein the thermoplastic organic, polymeric material has a solubility in dichloromethane of at least 50 g/L at 25° C. 
     
     
         25 . The process according to  claim 17 , wherein the thermoplastic polymeric material comprises at least one aliphatic-aromatic polyester or a combination of at least one aliphatic-aromatic polyester with at least on thermoplastic polymer which is not an aliphatic-aromatic polyester. 
     
     
         26 . The process according to  claim 25 , wherein the thermoplastic organic, polymeric material, besides the aliphatic-aromatic polyester, additionally comprises at least one further polymer which is different from aliphatic-aromatic polyesters and which is in particular selected from the group consisting of aliphatic polyesters, polyanhydrides, polyesteramides, modified polysaccharides and proteins and mixtures thereof. 
     
     
         27 . The process according to  claim 17 , wherein the active is liquid at 22° C. and 1013 mbar or has a melting point below 100° C. 
     
     
         28 . The process according to  claim 27 , wherein the active is an aroma chemical which is liquid at 22° C. and 1013 mbar, or a mixture of aroma chemicals which is liquid at 22° C. and 1013 mbar. 
     
     
         29 . A composition of microparticles filled with at least one active, obtainable by a process according to  claim 17 . 
     
     
         30 . A product comprising a composition according to  claim 29  in a proportion by weight of 0.01% to 80% by weight based on the total weight of the product. 
     
     
         31 . The use of the composition according to  claim 29  in a product selected from perfumes, washing and cleaning products, cosmetic products, personal care products, hygiene articles, foods, food supplements, fragrance dispensers and fragrances. 
     
     
         32 . The use of the composition according to  claim 29  for controlled release of actives.